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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2014 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: UnsignedIntEncoder.html 939 2015-05-29 01:16:17Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.jsimpledb.util;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import java.io.EOFException;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import java.io.IOException;<a name="line.11"></a>
<span class="sourceLineNo">012</span>import java.io.InputStream;<a name="line.12"></a>
<span class="sourceLineNo">013</span>import java.io.OutputStream;<a name="line.13"></a>
<span class="sourceLineNo">014</span>import java.nio.ByteBuffer;<a name="line.14"></a>
<span class="sourceLineNo">015</span><a name="line.15"></a>
<span class="sourceLineNo">016</span>/**<a name="line.16"></a>
<span class="sourceLineNo">017</span> * Encodes unsigned (i.e., non-negative) {@code int} values to/from binary, preserving sort order, and such<a name="line.17"></a>
<span class="sourceLineNo">018</span> * that the length of the encoding is optimized for values near zero and encoded values never begin with {@code 0xff}.<a name="line.18"></a>
<span class="sourceLineNo">019</span> */<a name="line.19"></a>
<span class="sourceLineNo">020</span>public final class UnsignedIntEncoder {<a name="line.20"></a>
<span class="sourceLineNo">021</span><a name="line.21"></a>
<span class="sourceLineNo">022</span>    /**<a name="line.22"></a>
<span class="sourceLineNo">023</span>     * Maximum possible length of an encoded value.<a name="line.23"></a>
<span class="sourceLineNo">024</span>     */<a name="line.24"></a>
<span class="sourceLineNo">025</span>    public static final int MAX_ENCODED_LENGTH = 5;<a name="line.25"></a>
<span class="sourceLineNo">026</span><a name="line.26"></a>
<span class="sourceLineNo">027</span>    /**<a name="line.27"></a>
<span class="sourceLineNo">028</span>     * Minimum value that triggers a multi-byte encoding.<a name="line.28"></a>
<span class="sourceLineNo">029</span>     */<a name="line.29"></a>
<span class="sourceLineNo">030</span>    public static final int MIN_MULTI_BYTE_VALUE = 0xfb;                       // values 0xfb ... 0xfe prefix multi-byte values<a name="line.30"></a>
<span class="sourceLineNo">031</span><a name="line.31"></a>
<span class="sourceLineNo">032</span>    private UnsignedIntEncoder() {<a name="line.32"></a>
<span class="sourceLineNo">033</span>    }<a name="line.33"></a>
<span class="sourceLineNo">034</span><a name="line.34"></a>
<span class="sourceLineNo">035</span>    /**<a name="line.35"></a>
<span class="sourceLineNo">036</span>     * Encode the given value.<a name="line.36"></a>
<span class="sourceLineNo">037</span>     *<a name="line.37"></a>
<span class="sourceLineNo">038</span>     * @param value value to encode<a name="line.38"></a>
<span class="sourceLineNo">039</span>     * @return encoded value<a name="line.39"></a>
<span class="sourceLineNo">040</span>     * @throws IllegalArgumentException if {@code value} is negative<a name="line.40"></a>
<span class="sourceLineNo">041</span>     */<a name="line.41"></a>
<span class="sourceLineNo">042</span>    public static byte[] encode(int value) {<a name="line.42"></a>
<span class="sourceLineNo">043</span>        final ByteWriter writer = new ByteWriter(UnsignedIntEncoder.encodeLength(value));<a name="line.43"></a>
<span class="sourceLineNo">044</span>        UnsignedIntEncoder.write(writer, value);<a name="line.44"></a>
<span class="sourceLineNo">045</span>        return writer.getBytes();<a name="line.45"></a>
<span class="sourceLineNo">046</span>    }<a name="line.46"></a>
<span class="sourceLineNo">047</span><a name="line.47"></a>
<span class="sourceLineNo">048</span>    /**<a name="line.48"></a>
<span class="sourceLineNo">049</span>     * Decode the given value.<a name="line.49"></a>
<span class="sourceLineNo">050</span>     *<a name="line.50"></a>
<span class="sourceLineNo">051</span>     * @param data encoded value<a name="line.51"></a>
<span class="sourceLineNo">052</span>     * @return decoded value<a name="line.52"></a>
<span class="sourceLineNo">053</span>     * @throws IllegalArgumentException if {@code bytes} contains an invalid encoding, or extra trailing garbage<a name="line.53"></a>
<span class="sourceLineNo">054</span>     */<a name="line.54"></a>
<span class="sourceLineNo">055</span>    public static int decode(byte[] data) {<a name="line.55"></a>
<span class="sourceLineNo">056</span>        final ByteReader reader = new ByteReader(data);<a name="line.56"></a>
<span class="sourceLineNo">057</span>        final int value = UnsignedIntEncoder.read(reader);<a name="line.57"></a>
<span class="sourceLineNo">058</span>        if (reader.remain() &gt; 0)<a name="line.58"></a>
<span class="sourceLineNo">059</span>            throw new IllegalArgumentException("encoded value contains extra trailing garbage");<a name="line.59"></a>
<span class="sourceLineNo">060</span>        return value;<a name="line.60"></a>
<span class="sourceLineNo">061</span>    }<a name="line.61"></a>
<span class="sourceLineNo">062</span><a name="line.62"></a>
<span class="sourceLineNo">063</span>    /**<a name="line.63"></a>
<span class="sourceLineNo">064</span>     * Encode the given value to the output.<a name="line.64"></a>
<span class="sourceLineNo">065</span>     *<a name="line.65"></a>
<span class="sourceLineNo">066</span>     * @param writer destination for the encoded value<a name="line.66"></a>
<span class="sourceLineNo">067</span>     * @param value value to encode<a name="line.67"></a>
<span class="sourceLineNo">068</span>     * @throws IllegalArgumentException if {@code value} is negative<a name="line.68"></a>
<span class="sourceLineNo">069</span>     */<a name="line.69"></a>
<span class="sourceLineNo">070</span>    public static void write(ByteWriter writer, int value) {<a name="line.70"></a>
<span class="sourceLineNo">071</span>        writer.makeRoom(MAX_ENCODED_LENGTH);<a name="line.71"></a>
<span class="sourceLineNo">072</span>        writer.len += UnsignedIntEncoder.encode(value, writer.buf, writer.len);<a name="line.72"></a>
<span class="sourceLineNo">073</span>    }<a name="line.73"></a>
<span class="sourceLineNo">074</span><a name="line.74"></a>
<span class="sourceLineNo">075</span>    /**<a name="line.75"></a>
<span class="sourceLineNo">076</span>     * Encode the given value and write it to the given {@link OutputStream}.<a name="line.76"></a>
<span class="sourceLineNo">077</span>     *<a name="line.77"></a>
<span class="sourceLineNo">078</span>     * @param out destination for the encoded value<a name="line.78"></a>
<span class="sourceLineNo">079</span>     * @param value value to encode<a name="line.79"></a>
<span class="sourceLineNo">080</span>     * @throws IOException if an I/O error occurs<a name="line.80"></a>
<span class="sourceLineNo">081</span>     * @throws NullPointerException if {@code out} is null<a name="line.81"></a>
<span class="sourceLineNo">082</span>     */<a name="line.82"></a>
<span class="sourceLineNo">083</span>    public static void write(OutputStream out, int value) throws IOException {<a name="line.83"></a>
<span class="sourceLineNo">084</span>        final byte[] array = new byte[UnsignedIntEncoder.MAX_ENCODED_LENGTH];<a name="line.84"></a>
<span class="sourceLineNo">085</span>        final int nbytes = UnsignedIntEncoder.encode(value, array, 0);<a name="line.85"></a>
<span class="sourceLineNo">086</span>        out.write(array, 0, nbytes);<a name="line.86"></a>
<span class="sourceLineNo">087</span>    }<a name="line.87"></a>
<span class="sourceLineNo">088</span><a name="line.88"></a>
<span class="sourceLineNo">089</span>    /**<a name="line.89"></a>
<span class="sourceLineNo">090</span>     * Encode the given value and write it to the given {@link ByteBuffer}.<a name="line.90"></a>
<span class="sourceLineNo">091</span>     *<a name="line.91"></a>
<span class="sourceLineNo">092</span>     * @param buf destination for the encoded value<a name="line.92"></a>
<span class="sourceLineNo">093</span>     * @param value value to encode<a name="line.93"></a>
<span class="sourceLineNo">094</span>     * @throws java.nio.BufferOverflowException if {@code buf} overflows<a name="line.94"></a>
<span class="sourceLineNo">095</span>     * @throws java.nio.ReadOnlyBufferException if {@code buf} is read-only<a name="line.95"></a>
<span class="sourceLineNo">096</span>     * @throws NullPointerException if {@code buf} is null<a name="line.96"></a>
<span class="sourceLineNo">097</span>     */<a name="line.97"></a>
<span class="sourceLineNo">098</span>    public static void write(ByteBuffer buf, int value) {<a name="line.98"></a>
<span class="sourceLineNo">099</span>        final byte[] array = new byte[UnsignedIntEncoder.MAX_ENCODED_LENGTH];<a name="line.99"></a>
<span class="sourceLineNo">100</span>        final int nbytes = UnsignedIntEncoder.encode(value, array, 0);<a name="line.100"></a>
<span class="sourceLineNo">101</span>        buf.put(array, 0, nbytes);<a name="line.101"></a>
<span class="sourceLineNo">102</span>    }<a name="line.102"></a>
<span class="sourceLineNo">103</span><a name="line.103"></a>
<span class="sourceLineNo">104</span>    /**<a name="line.104"></a>
<span class="sourceLineNo">105</span>     * Read and decode a value from the input.<a name="line.105"></a>
<span class="sourceLineNo">106</span>     *<a name="line.106"></a>
<span class="sourceLineNo">107</span>     * @param reader input holding an encoded value<a name="line.107"></a>
<span class="sourceLineNo">108</span>     * @return the decoded value, always non-negative<a name="line.108"></a>
<span class="sourceLineNo">109</span>     * @throws IllegalArgumentException if the encoded value is truncated<a name="line.109"></a>
<span class="sourceLineNo">110</span>     * @throws IllegalArgumentException if an invalid encoding is encountered<a name="line.110"></a>
<span class="sourceLineNo">111</span>     */<a name="line.111"></a>
<span class="sourceLineNo">112</span>    public static int read(ByteReader reader) {<a name="line.112"></a>
<span class="sourceLineNo">113</span>        try {<a name="line.113"></a>
<span class="sourceLineNo">114</span>            final int first = reader.readByte();<a name="line.114"></a>
<span class="sourceLineNo">115</span>            int value;<a name="line.115"></a>
<span class="sourceLineNo">116</span>            switch (first) {<a name="line.116"></a>
<span class="sourceLineNo">117</span>            case 0xfb:<a name="line.117"></a>
<span class="sourceLineNo">118</span>                value = reader.readByte();<a name="line.118"></a>
<span class="sourceLineNo">119</span>                break;<a name="line.119"></a>
<span class="sourceLineNo">120</span>            case 0xfc:<a name="line.120"></a>
<span class="sourceLineNo">121</span>                value = (reader.readByte() &lt;&lt; 8) | reader.readByte();<a name="line.121"></a>
<span class="sourceLineNo">122</span>                break;<a name="line.122"></a>
<span class="sourceLineNo">123</span>            case 0xfd:<a name="line.123"></a>
<span class="sourceLineNo">124</span>                value = (reader.readByte() &lt;&lt; 16) | (reader.readByte() &lt;&lt; 8) | reader.readByte();<a name="line.124"></a>
<span class="sourceLineNo">125</span>                break;<a name="line.125"></a>
<span class="sourceLineNo">126</span>            case 0xfe:<a name="line.126"></a>
<span class="sourceLineNo">127</span>                value = (reader.readByte() &lt;&lt; 24) | (reader.readByte() &lt;&lt; 16) | (reader.readByte() &lt;&lt; 8) | reader.readByte();<a name="line.127"></a>
<span class="sourceLineNo">128</span>                if (value + MIN_MULTI_BYTE_VALUE &lt; 0)<a name="line.128"></a>
<span class="sourceLineNo">129</span>                    throw new IllegalArgumentException("invalid unsigned int encoding with high bit set");<a name="line.129"></a>
<span class="sourceLineNo">130</span>                break;<a name="line.130"></a>
<span class="sourceLineNo">131</span>            case 0xff:<a name="line.131"></a>
<span class="sourceLineNo">132</span>                throw new IllegalArgumentException("invalid unsigned int encoding starting with 0xff");<a name="line.132"></a>
<span class="sourceLineNo">133</span>            default:<a name="line.133"></a>
<span class="sourceLineNo">134</span>                return first;<a name="line.134"></a>
<span class="sourceLineNo">135</span>            }<a name="line.135"></a>
<span class="sourceLineNo">136</span>            return value + MIN_MULTI_BYTE_VALUE;<a name="line.136"></a>
<span class="sourceLineNo">137</span>        } catch (IndexOutOfBoundsException e) {<a name="line.137"></a>
<span class="sourceLineNo">138</span>            throw new IllegalArgumentException("encoded value is truncated", e);<a name="line.138"></a>
<span class="sourceLineNo">139</span>        }<a name="line.139"></a>
<span class="sourceLineNo">140</span>    }<a name="line.140"></a>
<span class="sourceLineNo">141</span><a name="line.141"></a>
<span class="sourceLineNo">142</span>    /**<a name="line.142"></a>
<span class="sourceLineNo">143</span>     * Read and decode a value from the given {@link InputStream}.<a name="line.143"></a>
<span class="sourceLineNo">144</span>     *<a name="line.144"></a>
<span class="sourceLineNo">145</span>     * @param input input source for the encoded value<a name="line.145"></a>
<span class="sourceLineNo">146</span>     * @return the decoded value<a name="line.146"></a>
<span class="sourceLineNo">147</span>     * @throws IOException if an I/O error occurs<a name="line.147"></a>
<span class="sourceLineNo">148</span>     * @throws EOFException if an unexpected EOF is encountered<a name="line.148"></a>
<span class="sourceLineNo">149</span>     * @throws IllegalArgumentException if an invalid encoding is encountered<a name="line.149"></a>
<span class="sourceLineNo">150</span>     * @throws NullPointerException if {@code input} is null<a name="line.150"></a>
<span class="sourceLineNo">151</span>     */<a name="line.151"></a>
<span class="sourceLineNo">152</span>    public static int read(InputStream input) throws IOException {<a name="line.152"></a>
<span class="sourceLineNo">153</span>        final int first = input.read();<a name="line.153"></a>
<span class="sourceLineNo">154</span>        if (first == -1)<a name="line.154"></a>
<span class="sourceLineNo">155</span>            throw new EOFException();<a name="line.155"></a>
<span class="sourceLineNo">156</span>        final byte[] array = new byte[UnsignedIntEncoder.decodeLength(first)];<a name="line.156"></a>
<span class="sourceLineNo">157</span>        array[0] = (byte)first;<a name="line.157"></a>
<span class="sourceLineNo">158</span>        for (int i = 1; i &lt; array.length; i++) {<a name="line.158"></a>
<span class="sourceLineNo">159</span>            final int next = input.read();<a name="line.159"></a>
<span class="sourceLineNo">160</span>            if (next == -1)<a name="line.160"></a>
<span class="sourceLineNo">161</span>                throw new EOFException();<a name="line.161"></a>
<span class="sourceLineNo">162</span>            array[i] = (byte)next;<a name="line.162"></a>
<span class="sourceLineNo">163</span>        }<a name="line.163"></a>
<span class="sourceLineNo">164</span>        return UnsignedIntEncoder.read(new ByteReader(array));<a name="line.164"></a>
<span class="sourceLineNo">165</span>    }<a name="line.165"></a>
<span class="sourceLineNo">166</span><a name="line.166"></a>
<span class="sourceLineNo">167</span>    /**<a name="line.167"></a>
<span class="sourceLineNo">168</span>     * Read and decode a value from the given {@link ByteBuffer}.<a name="line.168"></a>
<span class="sourceLineNo">169</span>     *<a name="line.169"></a>
<span class="sourceLineNo">170</span>     * @param buf input source for the encoded value<a name="line.170"></a>
<span class="sourceLineNo">171</span>     * @return the decoded value<a name="line.171"></a>
<span class="sourceLineNo">172</span>     * @throws java.nio.BufferUnderflowException if {@code buf} underflows<a name="line.172"></a>
<span class="sourceLineNo">173</span>     * @throws IllegalArgumentException if an invalid encoding is encountered<a name="line.173"></a>
<span class="sourceLineNo">174</span>     * @throws NullPointerException if {@code buf} is null<a name="line.174"></a>
<span class="sourceLineNo">175</span>     */<a name="line.175"></a>
<span class="sourceLineNo">176</span>    public static int read(ByteBuffer buf) {<a name="line.176"></a>
<span class="sourceLineNo">177</span>        final byte first = buf.get();<a name="line.177"></a>
<span class="sourceLineNo">178</span>        final byte[] array = new byte[UnsignedIntEncoder.decodeLength(first)];<a name="line.178"></a>
<span class="sourceLineNo">179</span>        array[0] = first;<a name="line.179"></a>
<span class="sourceLineNo">180</span>        if (array.length &gt; 1)<a name="line.180"></a>
<span class="sourceLineNo">181</span>            buf.get(array, 1, array.length - 1);<a name="line.181"></a>
<span class="sourceLineNo">182</span>        return UnsignedIntEncoder.read(new ByteReader(array));<a name="line.182"></a>
<span class="sourceLineNo">183</span>    }<a name="line.183"></a>
<span class="sourceLineNo">184</span><a name="line.184"></a>
<span class="sourceLineNo">185</span>    /**<a name="line.185"></a>
<span class="sourceLineNo">186</span>     * Skip a value from the input.<a name="line.186"></a>
<span class="sourceLineNo">187</span>     *<a name="line.187"></a>
<span class="sourceLineNo">188</span>     * @param reader input holding an encoded value<a name="line.188"></a>
<span class="sourceLineNo">189</span>     */<a name="line.189"></a>
<span class="sourceLineNo">190</span>    public static void skip(ByteReader reader) {<a name="line.190"></a>
<span class="sourceLineNo">191</span>        final int first = reader.readByte();<a name="line.191"></a>
<span class="sourceLineNo">192</span>        if (first &gt;= MIN_MULTI_BYTE_VALUE)<a name="line.192"></a>
<span class="sourceLineNo">193</span>            reader.skip(first - MIN_MULTI_BYTE_VALUE + 1);<a name="line.193"></a>
<span class="sourceLineNo">194</span>    }<a name="line.194"></a>
<span class="sourceLineNo">195</span><a name="line.195"></a>
<span class="sourceLineNo">196</span>    /**<a name="line.196"></a>
<span class="sourceLineNo">197</span>     * Determine the length (in bytes) of an encoded value based on the first byte.<a name="line.197"></a>
<span class="sourceLineNo">198</span>     *<a name="line.198"></a>
<span class="sourceLineNo">199</span>     * @param first first byte of encoded value (in lower eight bits; other bits are ignored)<a name="line.199"></a>
<span class="sourceLineNo">200</span>     * @return the length of the encoded value (including {@code first})<a name="line.200"></a>
<span class="sourceLineNo">201</span>     * @throws IllegalArgumentException if the lower eight bits of {@code first} equal {@code 0xff}<a name="line.201"></a>
<span class="sourceLineNo">202</span>     */<a name="line.202"></a>
<span class="sourceLineNo">203</span>    public static int decodeLength(int first) {<a name="line.203"></a>
<span class="sourceLineNo">204</span>        first &amp;= 0xff;<a name="line.204"></a>
<span class="sourceLineNo">205</span>        if (first == 0xff)<a name="line.205"></a>
<span class="sourceLineNo">206</span>            throw new IllegalArgumentException("invalid unsigned int encoding starting with 0xff");<a name="line.206"></a>
<span class="sourceLineNo">207</span>        return first &lt; MIN_MULTI_BYTE_VALUE ? 1 : first - MIN_MULTI_BYTE_VALUE + 2;<a name="line.207"></a>
<span class="sourceLineNo">208</span>    }<a name="line.208"></a>
<span class="sourceLineNo">209</span><a name="line.209"></a>
<span class="sourceLineNo">210</span>    /**<a name="line.210"></a>
<span class="sourceLineNo">211</span>     * Determine the length (in bytes) of the encoded value.<a name="line.211"></a>
<span class="sourceLineNo">212</span>     *<a name="line.212"></a>
<span class="sourceLineNo">213</span>     * @param value value to encode<a name="line.213"></a>
<span class="sourceLineNo">214</span>     * @return the length of the encoded value, a value between one and {@link #MAX_ENCODED_LENGTH}<a name="line.214"></a>
<span class="sourceLineNo">215</span>     * @throws IllegalArgumentException if {@code value} is negative<a name="line.215"></a>
<span class="sourceLineNo">216</span>     */<a name="line.216"></a>
<span class="sourceLineNo">217</span>    public static int encodeLength(int value) {<a name="line.217"></a>
<span class="sourceLineNo">218</span>        if (value &lt; 0)<a name="line.218"></a>
<span class="sourceLineNo">219</span>            throw new IllegalArgumentException("value &lt; 0");<a name="line.219"></a>
<span class="sourceLineNo">220</span>        value -= MIN_MULTI_BYTE_VALUE;<a name="line.220"></a>
<span class="sourceLineNo">221</span>        if (value &lt; 0)<a name="line.221"></a>
<span class="sourceLineNo">222</span>            return 1;<a name="line.222"></a>
<span class="sourceLineNo">223</span>        int length = 2;<a name="line.223"></a>
<span class="sourceLineNo">224</span>        while ((value &gt;&gt;= 8) != 0)<a name="line.224"></a>
<span class="sourceLineNo">225</span>            length++;<a name="line.225"></a>
<span class="sourceLineNo">226</span>        return length;<a name="line.226"></a>
<span class="sourceLineNo">227</span>    }<a name="line.227"></a>
<span class="sourceLineNo">228</span><a name="line.228"></a>
<span class="sourceLineNo">229</span>    /**<a name="line.229"></a>
<span class="sourceLineNo">230</span>     * Encode the given value and write the encoded bytes into the given buffer.<a name="line.230"></a>
<span class="sourceLineNo">231</span>     *<a name="line.231"></a>
<span class="sourceLineNo">232</span>     * @param value value to encode<a name="line.232"></a>
<span class="sourceLineNo">233</span>     * @param buf output buffer<a name="line.233"></a>
<span class="sourceLineNo">234</span>     * @param off starting offset into output buffer<a name="line.234"></a>
<span class="sourceLineNo">235</span>     * @return the number of encoded bytes written<a name="line.235"></a>
<span class="sourceLineNo">236</span>     * @throws IllegalArgumentException if {@code value} is negative<a name="line.236"></a>
<span class="sourceLineNo">237</span>     * @throws ArrayIndexOutOfBoundsException if {@code off} is negative or the encoded value exceeds the given buffer<a name="line.237"></a>
<span class="sourceLineNo">238</span>     */<a name="line.238"></a>
<span class="sourceLineNo">239</span>    private static int encode(int value, byte[] buf, int off) {<a name="line.239"></a>
<span class="sourceLineNo">240</span>        if (value &lt; 0)<a name="line.240"></a>
<span class="sourceLineNo">241</span>            throw new IllegalArgumentException("value &lt; 0");<a name="line.241"></a>
<span class="sourceLineNo">242</span>        if (value &lt; MIN_MULTI_BYTE_VALUE) {<a name="line.242"></a>
<span class="sourceLineNo">243</span>            buf[off] = (byte)value;<a name="line.243"></a>
<span class="sourceLineNo">244</span>            return 1;<a name="line.244"></a>
<span class="sourceLineNo">245</span>        }<a name="line.245"></a>
<span class="sourceLineNo">246</span>        value -= MIN_MULTI_BYTE_VALUE;<a name="line.246"></a>
<span class="sourceLineNo">247</span>        int len = 1;<a name="line.247"></a>
<span class="sourceLineNo">248</span>        int mask = 0xff000000;<a name="line.248"></a>
<span class="sourceLineNo">249</span>        boolean encoding = false;<a name="line.249"></a>
<span class="sourceLineNo">250</span>        for (int shift = 24; shift != 0; shift -= 8, mask &gt;&gt;= 8) {<a name="line.250"></a>
<span class="sourceLineNo">251</span>            if (encoding || (value &amp; mask) != 0L) {<a name="line.251"></a>
<span class="sourceLineNo">252</span>                buf[off + len++] = (byte)(value &gt;&gt; shift);<a name="line.252"></a>
<span class="sourceLineNo">253</span>                encoding = true;<a name="line.253"></a>
<span class="sourceLineNo">254</span>            }<a name="line.254"></a>
<span class="sourceLineNo">255</span>        }<a name="line.255"></a>
<span class="sourceLineNo">256</span>        buf[off + len++] = (byte)value;<a name="line.256"></a>
<span class="sourceLineNo">257</span>        buf[off] = (byte)(MIN_MULTI_BYTE_VALUE + len - 2);<a name="line.257"></a>
<span class="sourceLineNo">258</span>        return len;<a name="line.258"></a>
<span class="sourceLineNo">259</span>    }<a name="line.259"></a>
<span class="sourceLineNo">260</span><a name="line.260"></a>
<span class="sourceLineNo">261</span>    /**<a name="line.261"></a>
<span class="sourceLineNo">262</span>     * Test routine.<a name="line.262"></a>
<span class="sourceLineNo">263</span>     *<a name="line.263"></a>
<span class="sourceLineNo">264</span>     * @param args command line arguments<a name="line.264"></a>
<span class="sourceLineNo">265</span>     */<a name="line.265"></a>
<span class="sourceLineNo">266</span>    public static void main(String[] args) {<a name="line.266"></a>
<span class="sourceLineNo">267</span>        for (String arg : args) {<a name="line.267"></a>
<span class="sourceLineNo">268</span>            byte[] bytes = null;<a name="line.268"></a>
<span class="sourceLineNo">269</span>            try {<a name="line.269"></a>
<span class="sourceLineNo">270</span>                bytes = ByteUtil.parse(arg);<a name="line.270"></a>
<span class="sourceLineNo">271</span>            } catch (IllegalArgumentException e) {<a name="line.271"></a>
<span class="sourceLineNo">272</span>                if (arg.startsWith("0x"))<a name="line.272"></a>
<span class="sourceLineNo">273</span>                    bytes = ByteUtil.parse(arg.substring(2));<a name="line.273"></a>
<span class="sourceLineNo">274</span>            }<a name="line.274"></a>
<span class="sourceLineNo">275</span>            if (bytes != null) {<a name="line.275"></a>
<span class="sourceLineNo">276</span>                System.out.println("Decoding bytes: " + ByteUtil.toString(bytes));<a name="line.276"></a>
<span class="sourceLineNo">277</span>                try {<a name="line.277"></a>
<span class="sourceLineNo">278</span>                    final long value = UnsignedIntEncoder.decode(bytes);<a name="line.278"></a>
<span class="sourceLineNo">279</span>                    System.out.println("0x" + ByteUtil.toString(bytes)<a name="line.279"></a>
<span class="sourceLineNo">280</span>                      + " decodes to " + value + " (" + String.format("0x%016x", value) + ")");<a name="line.280"></a>
<span class="sourceLineNo">281</span>                } catch (IndexOutOfBoundsException e) {<a name="line.281"></a>
<span class="sourceLineNo">282</span>                    System.out.println("Error decoding " + ByteUtil.toString(bytes) + ": " + e);<a name="line.282"></a>
<span class="sourceLineNo">283</span>                } catch (IllegalArgumentException e) {<a name="line.283"></a>
<span class="sourceLineNo">284</span>                    System.out.println("Error decoding " + ByteUtil.toString(bytes) + ": " + e);<a name="line.284"></a>
<span class="sourceLineNo">285</span>                }<a name="line.285"></a>
<span class="sourceLineNo">286</span>            }<a name="line.286"></a>
<span class="sourceLineNo">287</span>            Integer value = null;<a name="line.287"></a>
<span class="sourceLineNo">288</span>            try {<a name="line.288"></a>
<span class="sourceLineNo">289</span>                value = Integer.parseInt(arg);<a name="line.289"></a>
<span class="sourceLineNo">290</span>            } catch (IllegalArgumentException e) {<a name="line.290"></a>
<span class="sourceLineNo">291</span>                // ignore<a name="line.291"></a>
<span class="sourceLineNo">292</span>            }<a name="line.292"></a>
<span class="sourceLineNo">293</span>            if (value != null &amp;&amp; value.intValue() &gt;= 0) {<a name="line.293"></a>
<span class="sourceLineNo">294</span>                System.out.println("Encoding value " + value);<a name="line.294"></a>
<span class="sourceLineNo">295</span>                final ByteWriter writer = new ByteWriter();<a name="line.295"></a>
<span class="sourceLineNo">296</span>                UnsignedIntEncoder.write(writer, value);<a name="line.296"></a>
<span class="sourceLineNo">297</span>                System.out.println(value + " (" + String.format("0x%016x", value)<a name="line.297"></a>
<span class="sourceLineNo">298</span>                  + ") encodes to " + ByteUtil.toString(writer.getBytes()));<a name="line.298"></a>
<span class="sourceLineNo">299</span>            }<a name="line.299"></a>
<span class="sourceLineNo">300</span>        }<a name="line.300"></a>
<span class="sourceLineNo">301</span>    }<a name="line.301"></a>
<span class="sourceLineNo">302</span>}<a name="line.302"></a>
<span class="sourceLineNo">303</span><a name="line.303"></a>




























































</pre>
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